Rotary machine air deflector

ABSTRACT

A rotary machine includes a shaft extending through the rotary machine; a bearing positioned around the shaft; and an air deflector mounted on the shaft between the bearing and the shaft, wherein the air deflector has a first cylindrical body portion that is connected to a second cylindrical body portion with a ramp portion. A method for cooling a bearing positioned around a rotating shaft includes providing air to a cavity that surrounds a rotating shaft; deflecting the air towards an inner surface of a bearing that is positioned radially outward of the rotating shaft, wherein the air is deflected with an air deflector that is mounted on the rotating shaft; and flowing the air between an outer surface of the air deflector and the inner surface of the bearing.

CROSS-REFERENCE TO RELATED APPLICATION(S)

This application is a continuation of and claims priority to U.S.application Ser. No. 14/461,789, issued as U.S. Pat. No. 10,113,445,filed on Aug. 18, 2014, and entitled “Rotary Machine Air Deflector,” thedisclosure of which is incorporated by reference in its entirety.

BACKGROUND

The present invention relates to rotary machines, and in particular, toan air deflector for an air cycle machine.

Air cycle machines are used in environmental control systems in aircraftto condition air for delivery to an aircraft cabin. Conditioned air isair at a temperature, pressure, and humidity desirable for aircraftpassenger comfort and safety. At or near ground level, the ambient airtemperature and/or humidity is often sufficiently high that the air mustbe cooled as part of the conditioning process before being delivered tothe aircraft cabin. At flight altitude, ambient air is often far coolerthan desired, but at such a low pressure that it must be compressed toan acceptable pressure as part of the conditioning process. Compressingambient air at flight altitude heats the resulting pressurized airsufficiently that it must be cooled, even if the ambient air temperatureis very low. Thus, under most conditions, heat must be removed from airby the air cycle machine before the air is delivered to the aircraftcabin.

To condition the air as needed, air cycle machines include a fansection, a compressor section, and a turbine section that are allmounted on a common shaft. The compressor receives partially compressedair from the aircraft and further compresses the air. The compressed airthen moves through a heat exchanger and is cooled by the fan section.The air then moves through the turbine section where it is expanded foruse in the aircraft, for example, for use as cabin air. The turbinesection also extracts energy from the air and uses the energy to drivethe fan section and the compressor section via the common shaft.

Air cycle machines also include bearings that are positioned around thecommon shaft. The bearings are cooled by passing a cooling air flowthrough a cavity that is adjacent the bearing. The cooling air flow thenexits the cavity and is discharged from the air cycle machine into anambient. The cooling air flow is limited in that it can only cool thebearing using convective heat transfer. The cooling air flow is furtherlimited in that the cooling air flow in the cavity flows through acenter of the cavity, meaning a majority of the cooling air flow doesnot flow across a surface of the bearing.

SUMMARY

A rotary machine includes a shaft extending through the rotary machine;a bearing positioned around the shaft; and an air deflector mounted onthe shaft between the bearing and the shaft, wherein the air deflectorhas a first cylindrical body portion that is connected to a secondcylindrical body portion with a ramp portion.

A method for cooling a bearing positioned around a rotating shaftincludes providing air to a cavity that surrounds a rotating shaft;deflecting the air towards an inner surface of a bearing that ispositioned radially outward of the rotating shaft, wherein the air isdeflected with an air deflector that is mounted on the rotating shaft;and flowing the air between an outer surface of the air deflector andthe inner surface of the bearing.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a cross-sectional view of an air cycle machine.

FIG. 2A is a perspective view of an air deflector.

FIG. 2B is a cross-sectional side view of the air deflector seen in FIG.2A.

FIG. 3 is an enlarged cross-sectional view of the air deflector in a fansection of the air cycle machine.

DETAILED DESCRIPTION

In general, the present disclosure is an air deflector for use in arotary machine. The air deflector can be mounted on a shaft between abearing and the shaft to dissipate heat away from the bearing and out ofthe rotary machine. The air deflector includes a body with a borerunning through the body in which a shaft can be positioned. The body ofthe air deflector includes a first body portion, a ramp portion, and asecond body portion. The ramp portion is positioned between the firstbody portion and the second body portion. The ramp portion has a conicalshape with an incline to force cooling air flowing around the airdeflector outwards towards the bearing. The cooling air flowing acrossthe bearing can cool the bearing with convective heat transfer.

FIG. 1 is a cross-sectional view of air cycle machine 10. Air cyclemachine 10 includes fan section 12, compressor section 14, and turbinesection 16 that are all mounted on shaft 18. Shaft 18 rotates aroundcentral axis 20. Fan section 12 includes fan blade 30. Compressorsection 14 includes compressor inlet 40, compressor outlet 42, andcompressor nozzle 44. Turbine section 16 includes turbine inlet 50,turbine outlet 52, and turbine nozzle 54. Also shown in FIG. 1 is heatexchanger 60, housing 70, bearing 72, bearing sleeve 74, bearing foil76, bearing journal 78, cooling air flow 80, cooling air flow inlet 82,cavity 84, opening 86, and air deflector 100.

Shaft 18 is a rod, such as a titanium tie-rod, used to connect othercomponents of air cycle machine 10. Central axis 20 is an axis withrespect to which other components may be arranged.

Fan section 12 includes fan blade 30. Fan section 12 is mounted on shaft18. Fan blades 30 rotate around shaft 18. Fan section 12 typically drawsin ram air from a ram air scoop or alternatively from an associated gasturbine or other aircraft component. Fan section 12 may also be used todraw air through heat exchanger 60.

Compressor section 14 includes compressor inlet 40, compressor outlet42, and compressor nozzle 44. Compressor section 14 is mounted on shaft18. Compressor inlet 40 is a duct through which air is received to becompressed. Compressor outlet 42 is a duct through which air can berouted to other systems after it has been compressed in compressorsection 14. Compressor nozzle 44 is a nozzle section that rotatesthrough the air in compressor section 14. In particular, compressornozzle 44 is a rotor or impeller.

Turbine section 16 includes turbine inlet 50, turbine outlet 52, andturbine nozzle 54. Turbine section 16 is mounted on shaft 18. Turbineinlet 50 is a duct through which air passes prior to expansion inturbine section 16. Turbine outlet 52 is a duct through which air can berouted after it has been expanded to be used in other areas on anaircraft. For example, air can be routed out of turbine outlet 52 andinto a cabin for use as cabin air. Turbine nozzle 54 is a nozzle sectionthat extracts energy from air passing through turbine section 16. Inparticular, turbine nozzle 54 is a rotor or impeller. Air passingthrough turbine section 16 drives the rotation of turbine section 16 andany attached components, including shaft 18, fan section 12, andcompressor section 14.

Air is received in air cycle machine 10 at compressor inlet 40. The aircan be ram air from a ram air scoop or the air can be pulled into aircycle 10 using fan section 12 from an associated gas turbine or otheraircraft component. The air passes through compressor section 14 whereit is compressed with compressor nozzle 44 and then discharged out ofcompressor outlet 42. From compressor outlet 42, the air can passthrough heat exchanger 60. Fan section 12 may be used to draw airthrough heat exchanger 60. Air that exits heat exchanger 60 is thenrouted into turbine inlet 50. The air expands as it passes throughturbine section 16 and it drives turbine nozzle 54 before it isdischarged out of turbine outlet 52. Air that is discharged out ofturbine outlet 52 can then be routed to other parts of the aircraft, forexample, for use as cabin air.

Adjacent fan section 12 in air cycle machine 10 is housing 70. Housing70 forms an outer portion of air cycle machine 10. Bearing 72 ispositioned between shaft 18 and housing 70. Bearing 72 is a foil bearingin the embodiment shown in FIG. 1. Bearing 72 includes bearing sleeve74, bearing foil 76, and bearing journal 78. Bearing foil 76 ispositioned between bearing sleeve 74 and bearing journal 78. Bearingsleeve 74 forms an outer surface of bearing 72 and bearing journal 78forms an inner surface of bearing 72. The inner surface of bearingjournal 78 faces shaft 18. Air deflector 100 is mounted on shaft 18between bearing 72 and shaft 18 to dissipate heat out of bearing 72.

Cooling air flow 80 is bled from the air being routed from heatexchanger 60 to turbine inlet 50. Cooling air flow 80 is routed throughcooling air flow inlet 82 and through air cycle machine 10 to cavity 84.Cavity 84 is an open area surrounding shaft 18 that is defined by fansection 12 and turbine section 16. Air deflector 100 is positioned incavity 84 adjacent fan blade 30. Cooling air flow 80 will flow throughcavity 84 and will pass around air deflector 100 to cool bearing 72.Cooling air flow 80 will then exit through opening 86 that is formedbetween housing 70 and fan blade 30 and will be discharged into anambient out of air cycle machine 10.

Air cycle machine 10 is described as having fan section 12, compressorsection 14, and turbine section 16. In alternate embodiments, air cyclemachine 10 includes at least one of fan section 12 with fan blade 30mounted on shaft 18, compressor section 14 with compressor nozzle 44mounted on shaft 18, and turbine section 16 with turbine nozzle 54mounted on shaft 18.

FIG. 2A is a perspective view of air deflector 100. FIG. 2B is across-sectional side view of air deflector 100 seen in FIG. 2A. Airdeflector 100 includes body 102 and bore 104. Air deflector 100 furtherincludes first body portion 110, ramp portion 112, and second bodyportion 114. Also shown in FIGS. 2A-2B are first diameter D₁, seconddiameter D₂, and slope S.

Air deflector 100 includes body 102. Air deflector 100 can be made outof thermally conductive materials or thermally insulating materials.This can include metallic materials, plastic materials, ceramicmaterials, or any other suitable material. Bore 104 extends axiallythrough body 102 with a first opening at a first end of body 102 and asecond opening at a second end of body 102. Bore 104 runs through airdeflector 100 so that a shaft or other part can be positioned in bore104 of air deflector 100.

Body 102 of air deflector 100 includes first body portion 110, rampportion 112, and second body portion 114. First body portion 110 has acylindrical shape with first diameter D₁. A first end of first bodyportion 110 forms the first end of air deflector 100, and a second endof first body portion 110 is connected to a first end of ramp portion112. Ramp portion 112 has a conical shape and extends from firstdiameter D₁ to second diameter D₂. Ramp portion 112 has an incline withslope S. The second end of ramp portion 112 is connected to a first endof second body portion 114. Second body portion 114 is cylindricallyshaped with second diameter D₂. A second end of second body portion 114forms the second end of body 102.

Air deflector 100 can be used in any rotary machine that has a shaft anda bearing positioned around the shaft. This can include air cyclemachines and other turbine and motor driven compressors and fans. Airdeflector 100 is advantageous, as ramp portion 112 of air deflector 100forces cooling air to flow closer to a surface of a hot part that ispositioned around air deflector 100. The cooling air flow will absorbheat from the hot part as it flows across a surface of the hot part tocool the hot part. Air deflector 100 is further advantageous, as it islow weight and is easy and cost effective to manufacture.

FIG. 3 is an enlarged cross-sectional view of air deflector 100 in fansection 12 of air cycle machine 10. The portion of air cycle machine 10shown in FIG. 3 includes fan section 12 (including fan blade 30), shaft18, housing 70, bearing 72, bearing sleeve 74, bearing foil 76, bearingjournal 78, cavity 84, opening 86, and air deflector 100. Air deflector100 further includes body 102, including first body portion 110, rampportion 112, and second body portion 114.

Air cycle machine 10 includes fan section 12 that is mounted on shaft18. Shaft 18 is a common shaft that runs through air cycle machine 10and that rotates around central axis 20. Fan section 12 includes fanblade 30 that rotates with shaft 18 around central axis 20. Adjacent fanblade 30 is housing 70. Housing 70 forms an outer portion of air cyclemachine 10.

Positioned between shaft 18 and housing 70 is bearing 72. Bearing 72 isa foil bearing that includes bearing sleeve 74, bearing foil 76, andbearing journal 78. Bearing foil 76 is positioned between bearing sleeve74 and bearing journal 78. Bearing sleeve 74 forms an outer surface ofbearing 72 and bearing journal 78 forms an inner surface of bearing 72.The inner surface of bearing journal 78 faces shaft 18. Cavity 84 isformed between shaft 18 and the inner surface of bearing journal 78.Cooling air flow can be routed through cavity 84 to cool bearing 72. Thecooling air flow can then exit through opening 86. Opening 86 is anopening through bearing journal 78 between fan blade 30 and housing 70.After cooling air flows through opening 86 it can be discharged from aircycle machine 10 into an ambient.

Positioned in cavity 84 around shaft 18 is air deflector 100. Airdeflector 100 is mounted on shaft 18 so that it rotates with shaft 18around central axis 20. Air deflector 100 includes body 102 with firstbody portion 110, ramp portion 112, and second body portion 114. Rampportion 112 is positioned between first body portion 110 and second bodyportion 114. Ramp portion 112 has a conical shape with an incline toforce cooling air flowing through cavity 84 into an area between secondbody portion 114 and the inner surface of bearing journal 78.

Air deflector 100 transfers heat out of bearing 72 by forcing thecooling air closer to the inner surface of bearing journal 78. Thisallows for convective heat transfer, as heat is being transferred intothe air that is flowing across the inner surface of bearing journal 78.The cooling air flow that is flowing through cavity 84 between thesecond body portion 114 of air deflector 100 and bearing journal 78flows through opening 86 where it is discharged out of air cycle machine10. This discharges heat from bearing 72 into an ambient through thecooling air flow.

Without air deflector 100, bearing 72 would be cooled by flowing airthrough cavity 84. That cooling method would be inefficient, as coolingair flowing through cavity 84 would have a large area through which itflows. A majority of the cooling air would flow through the center ofcavity 84 between shaft 18 and journal bearing 68. This would make thecooling method inefficient, as a majority of the cooling air would notcome into contact with the inner surface of bearing journal 78.

Air deflector 100 is advantageous over prior art cooling systems, as thecooling air flow is forced into a smaller area between second bodyportion 114 of air deflector 100 and the inner surface of bearingjournal 78. This increases the effectiveness and efficiency of theconvective heat transfer, as more cooling air flow is coming intocontact with the inner surface of bearing journal 78. Air deflector 100thus improves the cooling of bearing 72 to make bearing 72 morereliable.

Air deflector 100 also provides several advantages for air cycle machine10. First, air deflector 100 makes air cycle machine 10 more effective,as less cooling air flow is needed to cool bearing 72. This means lesscooling air flow needs to be routed away from the main flow path throughair cycle machine 10, thus improving the overall efficiency of air cyclemachine 10. Second, as more air is kept in the main flow path throughair cycle machine 10, the heat exchanger has to do less work. This meansthe size and weight of the heat exchanger can be reduced. The improvedefficiency and effectiveness of air cycle machine 10 with air deflector100 outweighs any concerns about the weight or cost of adding airdeflector 100 to air cycle machine 10. Air deflector 100 greatlyimproves the thermodynamic performance of air that is flowing throughair cycle machine 10.

While the invention has been described with reference to an exemplaryembodiment(s), it will be understood by those skilled in the art thatvarious changes may be made and equivalents may be substituted forelements thereof without departing from the scope of the invention. Inaddition, many modifications may be made to adapt a particular situationor material to the teachings of the invention without departing from theessential scope thereof. Therefore, it is intended that the inventionnot be limited to the particular embodiment(s) disclosed, but that theinvention will include all embodiments falling within the scope of theappended claims.

The invention claimed is:
 1. A rotary machine comprising: a shaftextending through the rotary machine; a bearing positioned around theshaft; an air deflector mounted on the shaft between an inner surface ofthe bearing and the shaft, wherein the air deflector has a firstcylindrical body portion that is connected to a second cylindrical bodyportion with a ramp portion, and wherein an inner surface of the firstcylindrical body portion abuts an outer surface of the shaft; and acavity around the shaft defined by a housing and the bearing, whereinthe air deflector is positioned in the cavity so that cooling airflowing through the cavity will flow between an outer surface of the airdeflector and the inner surface of the bearing to cool the bearing. 2.The rotary machine of claim 1, and further comprising at least one ofthe following: a fan section with a fan blade mounted on the shaft; acompressor section with a compressor nozzle mounted on the shaft; or aturbine section with a turbine nozzle mounted on the shaft.
 3. Therotary machine of claim 1, wherein the bearing comprises a foil bearing.4. The rotary machine of claim 3, wherein the foil bearing comprises: abearing sleeve forming an outer surface of the foil bearing; a bearingjournal forming an inner surface of the foil bearing that faces theshaft; and a bearing foil positioned between the bearing sleeve and thebearing journal.
 5. The rotary machine of claim 1, wherein the airdeflector further comprises: a bore running through the air deflectorwith a first opening at a first end of the air deflector and a secondopening at a second end of the air deflector, wherein the shaft extendsthrough the bore.
 6. The rotary machine of claim 1, wherein the firstcylindrical body portion has a first diameter and the second cylindricalbody portion has a second diameter.
 7. The rotary machine of claim 6,wherein the second diameter is larger than the first diameter.
 8. Therotary machine of claim 6, wherein the ramp portion has a conical shapethat extends from the first diameter to the second diameter.
 9. Therotary machine of claim 1, the cooling air that flows through the cavitybetween the outer surface of the air deflector and the inner surface ofthe bearing convectively cools the bearing.
 10. The rotary machine ofclaim 1, wherein the ramp portion of the air deflector is configured toforce the cooling air that is flowing through the cavity closer to theinner surface of the bearing.
 11. A method for cooling a bearingpositioned around a rotating shaft, the method comprising: providing airto a cavity that surrounds the rotating shaft; deflecting the airoutwards from the shaft and towards an inner surface of the bearing thatis positioned radially outward of the rotating shaft, wherein the air isdeflected with an air deflector that is mounted on and abuts therotating shaft; and flowing the air between an outer surface of the airdeflector and the inner surface of the bearing.
 12. The method of claim11, wherein deflecting the air with an air deflector includes forcingthe air closer to the inner surface of the bearing using a ramp portionof the air deflector.
 13. The method of claim 11, wherein flowing theair between the outer surface of the air deflector and the inner surfaceof the bearing will cool the bearing with convective heat transferbetween the bearing and the air flowing across the inner surface of thebearing.
 14. The method of claim 11, wherein the air deflector has afirst cylindrical body portion that is connected to a second cylindricalbody portion with a ramp portion.
 15. The method of claim 14, wherein aninner surface of the first cylindrical body portion abuts an outersurface of the shaft.
 16. The method of claim 11, and furthercomprising: expelling the air out of the cavity surrounding the rotatingshaft.
 17. The method of claim 16, wherein expelling the air out of thecavity surrounding the rotating shaft includes expelling heattransferred from the bearing to the air flowing through the cavity outof the cavity and into an ambient.